Aging and prolonged use of contact lenses can cause eye diseases like glaucoma, macular degeneration, and corneal neovascularization. Common treatment methods such as eye drops require repetitive application because the cornea (the outer protective barrier of the eye) prevents more than 95% of the drugs from being absorbed. In addition, the drugs can be quickly washed out by tears, which is not ideal for treating chronic eye diseases. To address these issues, a team at Nanyang Technological University developed eye patches that, in mice, are long-lasting and efficiently deliver drugs to cure eye diseases.

The eye patches are equipped with two layers of dissolvable micrometer-sized needles. The inner base layer can dissolve quickly in water, while the outer layer dissolves slowly. Both layers contain drugs. When the eye patch is pressed onto the wet surface of the cornea, the needles penetrate into the cornea and detach within 30 seconds as the inner layer dissolves, delivering a strong initial dosage. After removing the eye patch, the outer layer of needles, which has remained embedded in the cornea, dissolves over several days, leading to a sustained release of the second dose. The efficacy of the eye patches was demonstrated in mice with corneal neovascularization (abnormal blood vessel growth in cornea), a condition that can be caused by long-term use of contact lenses. The mice treated with eye patches showed 90% reduction of the symptoms, compared to the eye drop treatment (only 40% effective).

Future studies should focus on better location and timing control of drug release for other eye conditions in human. For example, age-related chronic progressive eye diseases such as glaucoma and macular degeneration would require the needles reaching deeper layers in the eye and constant drug release over much longer periods of time.